mm: add build-time option for hotplug memory default online type
Memory hotplug presently auto-onlines memory into a zone the kernel deems
appropriate if CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y.
The memhp_default_state boot param enables runtime config, but it's not
possible to do this at build-time.
Remove CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE, and replace it with
CONFIG_MHP_DEFAULT_ONLINE_TYPE_* choices that sync with the boot param.
Selections:
CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE
=> mhp_default_online_type = "offline"
Memory will not be onlined automatically.
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO
=> mhp_default_online_type = "online"
Memory will be onlined automatically in a zone deemed.
appropriate by the kernel.
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_KERNEL
=> mhp_default_online_type = "online_kernel"
Memory will be onlined automatically.
The zone may allow kernel data (e.g. ZONE_NORMAL).
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_MOVABLE
=> mhp_default_online_type = "online_movable"
Memory will be onlined automatically.
The zone will be ZONE_MOVABLE.
Default to CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE to match the existing
default CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=n behavior.
Existing users of CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y should use
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO.
[gourry@gourry.net: update KConfig comments]
Link: https://lkml.kernel.org/r/20241226182918.648799-1-gourry@gourry.net
Link: https://lkml.kernel.org/r/20241220210709.300066-1-gourry@gourry.net
Signed-off-by: Gregory Price <gourry@gourry.net>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>